BIG Oil Leak after oil change, 98 Jetta

cowboyjack

Veteran Member
Joined
Sep 24, 2005
Location
Vail, Arizona
TDI
1998 Jetta TDI
1998 A3 Jetta TDI. Just bought it used.

Tried to change oil today. Drained. No problem. Old oil filter, apparently from a Firestone oil change... hard to take off, but okay.

Put drain plug back in, no problem. Put on brand new Mann W 840/2 oil filter. No problem. 4.5 liters of Rotella T 5w/40w synthetic. No problem.

Started the thing up... BIG problem. Oil GUSHING out of top of filter, apparently between filter and oil cooler, on left side looking in from front of car.

Maybe a bad filter? Tried another Mann filter. Same gushing mess.

Oil filter surface that mates with filter looks clean and smooth enough.

Tried the OLD Firestone filter that was on the car when I got it... NO leak whatsoever.

So off to Firestone. Got the same filter as the old one. Put it on. Same gushing oil leak.

Old Firestone filter back on, no leak.

9 hours. 100 degree heat. 4 gallons of oil, more or less. And the oil still isn't changed. Priceless?

I've been changing oil in cars & trucks for 35 years and never seen nothin' like this. Anyone else encountered this?

Can the previous oil change shop have screwed on the wrong oil filter hard enough to DENT the oil cooler so that it now leaks under normal filter installation tightening?

Should I pull the oil cooler next and replace the sender unit, the O ring above, the stud and the locknut AND the cooler?

Suggestions? Ideas?

thanks in advance
 

jasonTDI

TDI GURU Vendor , w/Business number
Joined
Apr 26, 2001
Location
Oregon, WI
TDI
20' RAM 3500 CCLB dually HO/Aisan. 2019 Cherokee 2.0T
Sounds like an oil cooler replacement to me. What a drag.
 

cowboyjack

Veteran Member
Joined
Sep 24, 2005
Location
Vail, Arizona
TDI
1998 Jetta TDI
possible oil pump bypass problem?

Hey,

Made a couple of calls... might it be an oil pump bypass valve problem? Oil pressure shooting up so high it is blowing oil out between the filter and the oil cooler?

I live out in the country so don't really have any way to get the Jetta to a shop to get a manual oil pressure reading short of calling a tow truck...

I was thinking about just ordering a new oil pump and pan gasket and swapping it out... seems easier than the oil cooler replacement and it certainly can't hurt to have a new oil pump, can it?
 

jasonTDI

TDI GURU Vendor , w/Business number
Joined
Apr 26, 2001
Location
Oregon, WI
TDI
20' RAM 3500 CCLB dually HO/Aisan. 2019 Cherokee 2.0T
Good point.

Prior oil history if unknown might warrant it. But it still dosen't explain the one filter working and the rest not.
 

pinehead

Veteran Member
Joined
May 19, 2003
Location
Treasure Coast, FL
TDI
Passat
Isnt this oil cooler held on by a big nut in the center? Where the oil filter spins on?

The nut is the piece where the oil filter spins on. If this nut was loose and hanging down would it cause the filter and or the oil cooler housing not to seat fully?

I'm saying this because I had a leak there once too. Albeit a small one. Tightening this nut fixed my leak.

I'm pretty sure it is........ If this nut backs off after lots of oil changes I think the oil cooler can seperate from the mount causing a leak like you describe. Also, if it backs off and the o-ring gets pinched improperly (from tightening the filter), it could leak there too. I think there is an o-ring on top of the oil cooler too? This is the seal I'm refering to.

Worth looking at if you havent already. I just cant remember what is in there? Been a while since I messed with one.

AJ
 
Last edited:

cowboyjack

Veteran Member
Joined
Sep 24, 2005
Location
Vail, Arizona
TDI
1998 Jetta TDI
Pinehead,

Thanks. Yup, that locknut that's on the stud that the oil filter spins onto was sorta loose and I did tighten it up.

Oil still pours out (big squirting stream) between oil filter and cooler when engine is running -- empties oil pan within less than a minute, I would estimate. (No, I don't run it long enough to empty the engine.)

Leaks is isolated to between oil filter and oil cooler on left side as you look in from front of car.

Still baffled.

I'm gonna swap out the oil pump later today per recommendation of a very experienced TDI mechanic, try a VW OEM oil filter, and see if that resolves it.
 

cowboyjack

Veteran Member
Joined
Sep 24, 2005
Location
Vail, Arizona
TDI
1998 Jetta TDI
solved, maybe

Lest I speak too soon...

UPS dropped off an overnight oil pump, dropped the pan, (dang those last two screws are hard to find), hooked it up, (no shavings in pan, everything looked really clean), put on a Firestone oil filter, snugger than I usually put 'em on, filled 'er with oil... cranked her up... and NO LEAK! Yahoo! NO LEAK! Mild dance of joy and ebulance.

Now to wash the oil out of my hair with Dawn dishwashing soap.

I'll still get the OEM VW filter and change the oil one more time with Rotella T 5w/40w per advice here...

Thanks again for all the help, here and by PM.
 

cowboyjack

Veteran Member
Joined
Sep 24, 2005
Location
Vail, Arizona
TDI
1998 Jetta TDI
BBBAAADDD Mann oil filters?

Put on the OEM VW filter this morning, added the Rotella T.... NO leaks!

Happy dance!

Couple folks emailed me... might be a bunch of BAADDD Mann oil filters out there? First time I ever put on three bad filters in a row... but I wasn't the only one with leaking Mann filters.

NO MORE oil leak, lest I speak too soon....

Again, as a Newbie to TDIs... amazed at all the helpful input, thank you one and all.
 
Top